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Watt Calculator for Generator

Buying a solar generator is the first big step in making your way toward energy independence. To make sure you get one that’s big enough to meet your needs, you need to use a watt calculator to see how much power your generator can produce. 

It can be daunting at first to deal with complicated electrical equations, but once you’ve wrapped your head around some simple fundamentals, you’ll see just how easy it can be.

Using a Watts Calculator for a Generator

generator watts calculator

The first step you need to take is to use an online watts calculator to figure out what your solar needs are. This varies from household to household and depends on things like which appliances you want to power and for how long. 

Bearing that in mind, the average household uses about 30 kWh (kilowatt-hours) of electricity per day, so that’s the number we’re using in our calculations here. To convert that to the units we’re using here, check out our kilowatt-hour conversion calculator.

You can also use your utility bills to get an idea, although most utility companies measure the amount of energy you use each month in kilowatt-hours. 

The bare necessities will mostly be used during an emergency like a power outage, or even when you’re just out camping and don’t need a lot of electrical appliances. 


To figure out the output of your generator, there are a few things you can do. 

Start off by looking at your generator’s maximum power output. This determines the number of appliances you can power at once. For example, the EcoFlow Delta 1800 Solar Panel Kit has an output of 1,800 W. 

generator watt calculator

This means you can run up to 1,800 W of appliances at once. Given that small equipment like lightbulbs and fans use around 25 to 80 watts, and larger ones like TVs use around 200 watts, you can run quite a lot from this small unit.

To figure out if a generator is powerful enough, simply subtract the total continuous watt usage of you house (the wattage of all the appliances you have running at once, which averages to around 1,250 watts) from the output value of the generator:

Total Wattage = Generator Output – Power Draw

          = 1,800 – 1,250

          = 550W

This means the EcoFlow Delta, in this example, can power all the appliances in your house at the same time, with around 550W left over to make up for any margin of error.     

The Right Generator for You

The right generator does what it needs to, and exactly what it does is up to you. Having a particular purpose in mind when picking out a generator is going to smoothen out the process. 

The following are examples of three main uses that can be used as a guideline for what you’d like a generator to do. 


Starting with the most obvious one, a generator can often be used as a backup power or even a primary source of power for your home. 

Using a generator like the Bluetti AC200 Max in combination with a few solar panels can be a great option for an off-grid home. You can also use a solar load calculator to determine the total amount of power you need to generate with this solar panel and generator combination. 

watt generator calculator


For all the fun and outdoor activities, you can look into a generator for things like camping trips, DIY activities, and even for your RV. 


The generator can also be used to solely power your tools, helping you with construction and farm work whenever you need it. When working with circuits and the like, it’s good to convert watts to volts to compensate for the circuit’s resistance, if any are present. 

Why Is Size Important?

A generator’s size is important because it determines how much power you’ll have available during a power outage. The energy that’s produced by a generator is typically measured in kilowatts (kW).

Before buying any generator, be sure to know how much power in watts it can generate and how much power all of your electricals need to operate. You may want to convert watts to kilowatts to make the math behind it a little easier.

You could also use a nifty tool like a generator size calculator to find the perfect size to suit all of your requirements. The size of the generator you want depends on the voltage and power output that you’ll need.

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